Leadership Cartels in Industries with Differentiated Products.

This article analyses cartels that act as a Stackelberg leader with respect to a competitive fringe in industries supplying differentiated products. The main objectives are to investigate how cartel stability changes with the degree of differentiation and the cartel size, to predict endogenous cartels and to carry out a welfare analysis. Both repeated and static games are considered as well as industries competing in quantities and prices.CARTELS ; GAMES ; COMPETITION ; SIZE OF INDUSTRY

Exact analytical helmholtz bright and dark solitons

In this paper, exact analytical Helmholtz bright and dark soliton solutions for a Kerr nonlinearity are presented. Numerical simulations verify that these solutions are both robust and act as attractors in nonlinear beam dynamics. Results dealing with the coherent interaction of Helmholtz bright solitons are also presented, for the first time. These considerations extend previous (paraxial) studies that are only valid for vanishingly small interaction angles

Bistable dark solitons of a cubic-quintic Helmholtz equation

We report, to the best of our knowledge, the first exact analytical bistable dark spatial solitons of a nonlinear Helmholtz equation with a cubic-quintic refractive-index model. Our analysis begins with an investigation of the modulational instability characteristics of Helmholtz plane waves. We then derive a dark soliton by mapping the desired asymptotic form onto a uniform background field, and obtain a more general solution by deploying rotational invariance laws in the laboratory frame. The geometry of the new soliton is explored in detail, and a range of new physical predictions is uncovered. Particular attention is paid to the unified phenomena of arbitrary-angle off-axis propagation and non-degenerate bistability. Crucially, the corresponding solution of paraxial theory emerges in a simultaneous multiple limit. We conclude with a set of computer simulations that examine the role of Helmholtz dark solitons as robust attractors

Helmholtz algebraic solitons

We report, to the best of our knowledge, the first exact analytical algebraic solitons of a generalized cubic-quintic Helmholtz equation. This class of governing equation plays a key role in photonics modelling, allowing a full description of the propagation and interaction of broad scalar beams. New conservation laws are presented, and the recovery of paraxial results is discussed in detail. The stability properties of the new solitons are investigated by combining semi-analytical methods and computer simulations. In particular, new general stability regimes are reported for algebraic bright solitons

Exact soliton solutions of the nonlinear Helmholtz equation: communication

Exact analytical soliton solutions of the nonlinear Helmholtz equation are reported. A lucid generalization of paraxial soliton theory that incorporates nonparaxial effects is found